Thin macroporous silicon heterojunction solar cells

Abstract

Abstract We demonstrate the processing of a heterojunction solar cell from a purely macroporous silicon (MacPSi) absorber that is generated and separated from a monocrystalline n‐type Cz silicon wafer by means of electrochemical etching. The etching procedure results in straight pores with a diameter of (4.7 ± 0.2) µm and a distance of 8.3 µm. An intrinsic amorphous Si (a‐Si)/p + ‐type a‐Si/indium tin oxide (ITO) layer stack is on the front side and an intrinsic a‐Si/n + ‐type a‐Si/ITO layer stack is on the rear side. The pores are open when depositing the layers onto the 3.92 cm 2 ‐sized cell. The conductive layers do not cause shunting through the pores. A silicon oxide layer passivates the pore walls. The energy‐conversion efficiency of the (33 ± 2) µm thick cell is 7.2%. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)